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FFmpeg has access to many filters and more are added on a regular basis. To see what filters are available with your build see ''ffmpeg -filters''. Refer to the [http://ffmpeg.org/libavfilter.html libavfilter documentation] for more information and examples. This wiki page is for user contributed examples and tips. Contributions to this page are encouraged.

''iw'' is input width. In this example the input width is 640. 640/2 = 320. The ''-1'' tells the scale filter to preserve the aspect ratio of the output, so in this example the scale filter will choose a value of 240. See the [http://ffmpeg.org/libavfilter.html libavfilter documentation] for additional information.